N55 high pressure fuel pump long crank

image Picture of a high pressure fuel pump on a 2012 F10 N55 engine,,,customer complaints of long crank during start up,,,integrated fault memory,,,no faults,,,,I then performed fuel rail pressure test was ok,,,,performed fuel injector leakage test ok,,,performed fuel pressure holding pressure after shutting off ok.,,,so there are only a couple things that can cause long crank,,,,number 1 the high pressure fuel pump,,,number 2 low fuel pressure sensor,,,,ok 3 things fuel injector bad or leaking,,,,if a fuel injector is bad you would have rough running or fuel coming out the exhaust,,,,and we don’t have that,,,so the problem is fuel pump or low fuel pressure sensor,,,,and there are no faults for the sensor,,,and fuel rail pressure was ok.image So we decided to remove the high pressure fuel pump,,,,we have to remove this oil sensor which sits right behind the high pressure fuel pump,,,,you have to remove it to gain access to the rear bolt for the high pressure fuel pum.image Here is the small hole in the engine block where the oil sensor is located.,,,,on the old N54 that sensor was not in the way of replacing the fuel pump,,,,,they changed that on the N55.image Here is the old and the new fuel pumps,,,there is no change,,,,,this fuel pump is the same in the N54,,,,when the N54 came out we were replacing the high pressure fuel pump everyday,,,the first couple of designs were very bad ,,,,they finally go it right after all these years.

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22 Responses to N55 high pressure fuel pump long crank

  1. a.a. says:

    I can vouch for the latest design finally getting it right (fingers crossed) but in my case it took 2 tries before landing “the good one”


    • Amen,,,,I remember when the high pressure fuel pumps came out on the N54 engine,,,and we were replacing them everyday,,,,I remember I put a new one in a car,,,,,and went on a test drive with the new fuel pump,,,,on the test drive the new fuel pump failed and left me stranded on the test drive,,,,had to have the car towed back to the dealer and put another fuel pump in the car again.


  2. Patrick says:

    Have a question on the fuel pump replacement, do you need to reprogram anything if you install a remanufactured pump on a 2011 E90 N55 manual rwd? I’ve been experiencing the cold start issue for about 6 months now and it’s happening more and more often if I left the car in garage even for just couple days.


    • No you don’t have to programm anything when replacing the high pressure fuel pump,,,I recommend to also replace the low fuel pressure sensor if this model has one,,,,it should sit on the fuel feed line to the high pressure fuel pump if this car has one.


      • Patrick says:

        Thanks very much for the QUICK response!! About my situation, I don’t have the long crank symptoms like your original post mentioned, rather crank up fine on first try then struggle to maintain idling speed and eventually stalled. Usually on the subsequent start it will be ok, sometimes need a 3rd start, there’s no check engine light either. I don’t have the tools to do the leak test but will definitely look into low fuel pressure sensor. For the remanufacture pump, is there a particular updated version now from BMW? I’ve gathered most online parts vendor are selling this one (#13517616446)


      • Yes that fuel pump should be fine.


  3. Glenn Munro says:

    Hi Andreas, Ill try and be quick to the point. I bought a 2010 335i with an N55 engine last Sept with 98k on the clock. After 1 month it developed a rod knock. As I bought it privately there was no warranty. So as I have always done my own mechanical work and at 60 years of age I replaced the engine with a 38k 2012 N55 from a write off that I was told was ‘the same engine as my model” . Unfortunately there has been some subtle differences that have caused a few nightmares eg Coolant pipe around the turbo is different and doesn’t fit to existing hoses (fixed) and the 2012 engine has the new Bosch High Pressure fuel pump. I made enquiries about whether the new fuel pump would need reprogramming of my computer but I was told ” no it should be fine as only the pressures are measured”. OK so the new N55 started first go the threw an engine light and code showed high pressure in the fuel rail. This told me that the fuel regulator in the 2012 HPFP was not talking to my 2010 computer so it couldn’t regulate the pressure. I made a few enquiries and no one could help me. Ok so I decided to take the old fuel pump off my old N55 and fit it to the new N55. It has taken a while but here is my question……With the old pump it just slides off the vacuum pump shaft but the new engine the Bosch pump will not slide off the shaft . It gets to about 5mm then stops and no level of persuasion will remove it. My question is how do you separate the fuel pump body from the vacuum pump body in a 2012 N55 and will the older pump fit or have they changed the vacuum pump ? I have gone and purchased all the fuel, lines for both pumps but I would prefer the old pump on the engine so the computer can talk to it. Any suggestions Mate as I am getting desperate? Cheers Glenn


    • The HPFP should just release,,,,do you have the 3 Allen head bolt removed ,,,,you also have the in and out steel fuel lines removed,,,,there is no special tricks,,,,,on some engine blocks there sits a oil pressure switch right behind the HPFP which might be stopping you from pulling the HPFP off,,,,question for you did you use the original or the newer engine wiring harness that came with the newer engine,,,,,because there might be a different between the 2 harness which could cause weird faults,,,,,also did you calibrate the fuel injectors to the DME


      • Glenn Munro says:

        Thanks for the reply Andreas. The older N54/early N55 continental HPFP just slides straight off the vacuum pump but I have the new Bosch HPFP introduced in 2012 on my new engine. It wont slide off like the old one as it has a metal blade on the end of a shaft that is linked to the pulsing sensor. It is basically joined to the vacuum pump so the whole lot has to come off. I am going to order the special tools for holding the Vacuum pump sprocket and chain at the front and put my old vacuum pump and HPFP on so all the electronics are compatible. No I didn’t calibrate the old DME to the new engines injectors ….thanks for the tip. Have you ever changed a vacuum pump on an N55? I’m hoping the sprocket and chain sits firmly with the special tools while I change the vacuum pump. Have to any precautions I should be aware of?




      • No I haven’t replaced a vacuum pump on a N55.


  4. Guilherme Costa says:

    Good evening,

    I have a 2011 BMW 335i with a feed line that does not have the low pressure sensor on it. Where should I be looking for the low pressure sensor? I want to change the low pressure sensor first to ensure that it is not my HPFP.



    • The low pressure fuel sensor is on the fuel feed line to the back of the high pressure pump,,,,,it sits under the intake manifold,,,,,about 5 inches behind the high pressure fuel pump screwed on the fuel line


  5. sam says:

    on the f10 n55 my rail pressure reads 1000psi. On my buddys car which is same exact car same year same everything his reads 1700psi……Im having rough idle issue i restart car after an hour of sitting? do i have a HPFP issue?


  6. Yes your pressure should be higher then that,,,,,do you have any engine faults


  7. Dennis says:

    Hi, just picked up the car after the valve stem seal replacement ( 2012 x5 N63) and the car was returned with reduced power/engine malfunction. The dealer states that its HPFP though the car run fine with no CE light before the service. The codes I got with ISTA are 002B2B ‘Fuel high pressure 2, plausability’ and 002B2D ‘Fuel High pressure 2, cold start’. So how can i determine which of the HPFP is defective? Or how can I test the with ISTA? Thanks


  8. John says:

    Question, on N55 Can you just unplug the fuel rail plug at the back instead of disconnecting the battery?


    • Yes,,,I never disconnect the the battery when replacing the high pressure fuel pump


      • John says:

        I’m replacing the valve cover gasket. I was told it’s a good idea to disconnect the battery so it doesn’t wake up and cycle fuel why you have the fuel rail off. I see a plug at the back of the rail so I was thinking why not just unplug that? Seems like that would do the same thing.


      • Yes that is true the fuel pump could wake up and you get a taste of gasoline it has happen to me several times,,,a little gasoline at work never hurts,,,,lol


  9. dau kho says:

    Hello bmwtechnician,
    I have 29F2 code and radiator fan is running full speed after 5 second.
    I changed after market the HPFP and High and Low pressure sensor, The Low pressure 72 psi and High rail pressure 110 psi at idle. Would you give me advise, I’m appreciate, Thanks


    • First what type of engine and car do we have,,,,also after you replaced the HPFP and low pressure sensor will the fault not clear and comes back,,,,also if your radiator fan runs at high speed you have something else wrong like maybe water pump and t-stat


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